Figure 1

B. abortus induces secretion of MMP-9 from astrocytes. Astrocytes were infected with B. abortus at different multiplicities of infection (MOI). MMP-9 production was determined by zymography (A) and ELISA (B) at 48 hours post infection. For MMP activities, the supernatants from infected and non-infected astrocytes were incubated with a fluorescein-conjugated gelatin substrate that produces highly fluorescent peptides when gelatin is digested. Data are expressed in fluorescence units informed by the fluorometer (C). MMP-9, as determined by zymography, was also induced in astrocytes infected with B. canis, B. melitensis and B. suis (D). Phorbol myristate acetate (PMA) was used as a positive control. Bars express the mean ± SEM of duplicates. Data shown are from a representative experiment of three performed. ***P < 0.001 versus non-infected (NI) astrocytes.